The subject of the invention is a method and apparatus for compiling or arranging groups of filter segments in a continuous endwise manner in a process of producing multi-segment filters used in tobacco industry for cigarettes.
There is a demand in tobacco industry for multi-segment filters used in producing cigarettes. The filters consisting of at least two types of segments made of different filtrating materials. They may be soft filters filled with, e.g., fibrous material, paper, monoacetate or hard segments filled with granulate, sinter elements or hollow cylinders. A compiled set of filter segments is then divided into filters used for producing cigarettes. One method of compiling multi-segment filters is a crosswise method, the principle of which has been presented many times in patent descriptions belonging to a German company HAUNI AG.
One such description is a published USA patent application No. US 2004/237972 A1 dealing with an apparatus for compiling groups of filter segments for producing multi-segment filters in a continuous manner, operating in the crosswise method. The apparatus is separated or divided into a certain number of individual functional units or modules set or arranged together. At least two different types of filter segments are used in each produced multi-segment filter. The filter segments are transported and forwarded by properly set or arranged drums, on which cutting of filter segments and arranging groups of filter segments is effected. The groups of segments compiled transversely to the axis of a group of filter segments are then transported using drums or a belt conveyor equipped with flutes for receiving the filter segments. The flutes are arranged transversely to the direction of transport. The filter segments are then delivered to a commonly known device for producing endless filter rod. The crosswise method of compiling multi-segment filters is very expensive since many intermediate drums and cooperating cutting units are used in the apparatus.
Another method of compiling or arranging multi-segment filters is an endwise method. The endwise method has been presented many times in patent descriptions belonging to an English company, MOLINS Ltd. For example, British patent No. GB 971491 discloses a machine for producing multi-segment filters having two different filter segments. The filter is produced by cutting filter rods arranged on periphery of two separate drums using circular knives. Short filter segment elements must be guided over the drums with arch guides arranged coaxially with the drums. The width of the guides is at least half the length of the segments being cut, which may cause the segments to be incorrectly position ed in an uncontrolled manner and, as a result, they may be damaged. A set of cut segments is drawn out of each flute of the drum with the aid of a chain assembly having dogs. The chain assembly always operates in a vertical plane deflected through a slight angle from the axis of the cutting drum. The process of drawing the set of segments out is effected in an uncontrolled manner with the result that single segments may fall out of the set being transported. Moreover when short segments hit the back side of the first segment of the set with a dog, a segment on the opposite end of the set springs back from the rest of segments and moves separately for a short instant, which makes leading the short segments out more difficult. Segments are then displaced from the chain assembly to an intermediate disc with the aid of drivers arranged on periphery of a disc mounted coaxially with a chain sprocket of the chain assembly and are farther displaced in an endwise manner along a horizontal path to a worm drum which controls the flow of segments, whereas prior to entering the worm drum the segments of the other type prepared by cutting filter rods on the other drum are inserted in a similar way into empty spaces between the segments of the first type, the spaces being obtained during separating the segments in a hitting manner. In the said apparatus movement of the segments both on consecutive straight and arch-like parts of segment trajectory, where direction is changed, is effected with different means that must be synchronised with each another. In another version of the said machine presented in a British patent description No. GB 1578738 technical means are applied in order to position and group segments cut on drums prior to advancing them for farther technological operations, whereas filter rods are cut to unequal segments.
The inventive method concerns compiling groups of filter segments according to a continuous endwise manner in a process of producing multi-segment filters used in tobacco industry for cigarettes, where segments in each consecutive module, in which segments of one type are prepared, are passed to a transferring element which displaces the segments onto an exit path. In the method, in each module equal segments of one type are passed at a uniform rate to a transferring element which displaces each segment separately onto the exit path with the aid of drivers radially spaced on periphery of the transferring element, whereas setting of segments of each type in groups of segments positioned repeatedly on the exit path is defined by delay in collecting the segments by the transferring element in each module. Uniform setting of equal segments of one type on the exit path is effected with the aid of the transferring element provided with the drivers spaced uniformly on the periphery of the transferring element and non-uniform setting of equal segments of one type on the exit path is effected with the aid of the transferring element provided with the drivers spaced non-uniformly on the periphery of the transferring element, whereas the setting of the segment on the exit path depends on a distance between the segment passed at the uniform rate to the transferring element and the driver. The presented method enables setting a stream of groups of segments, each group consisting of many segments presenting all types of segments in the demanded filter where the sequence of setting the segments in groups is maintained and repeated.
The subject of the invention is construction of apparatus comprising at least two similar modules, and each module is provided with a cutting drum of a horizontal axis with flutes spaced on the circumference surface, of axes parallel to the axis of the drum, at the inlet the drum being connected to a container of filter rods of length which is n-multiplicity of a segment length, and circular knives cooperating with the drum, whereas filter rods cut into sets of segments are drawn out of the flutes into a guiding channel with the aid of dogs mounted on a loop-closed chain, the trajectory of which, in the area of the sets of the segments being drawn out of flutes is in principle parallel to the axis of the flute, and moreover each module is provided with a separator which separates single segments out of a stream of the sets of the segments, and is also provided with a transferring element, which collects the separated segments and places them onto an exit path.
According to the invention the apparatus is provided with a movable guiding element cooperating in synchronism with the cutting drum, situated by the cutting drum and forming a wall closing the channel for the sets of the segments drawn out of the flutes of the cutting drum, whereas the set of filter segments led through the channel by the dog of the chain is taken possession of by a worm surface of a pushing together drum positioned over the channel, the drum passing the segments for separating, the pitch of the worm surface becoming diminished in direction of movement of the segments down to the value corresponding to the length of the set of filter segments, and the separator of the segment situated at the end of the channel constitutes a disc cam of a rotation axis in principle parallel to the axis of the segment passed for separating, the disc cam pushing the segment out in a direction perpendicular to the axis of the segment passed for separating onto the rotary assembled transferring element between two neighbouring drivers spaced radially on periphery of the transferring element.
It is advantageous that the movable guiding element constitutes a multi-flute rotary assembled shaft, whereas the axes of the flutes of the multi-flute shaft in the area of guiding the set of filter segments being drawn out of the drum may be parallel to the axis of the cutting drum so that the axis of the set of filter segments is in principle parallel to the axis of the cutting drum and the height of the guiding channel is constant or the said axes may be askew to the axis of the cutting drum so that the guiding surface of the shaft is inclined with reference to the axis of the set of filter segments and the height of the guiding channel for the front face of the first segment of the set of filter segments is constant whereas the axis of the set of filter segments is in principle parallel to the axis of the cutting drum.
As an alternative the movable guiding element constitutes an endless belt with flutes in principle parallel to the axis of the cutting drum in the area of the sets of the segments being drawn out of the drum. The cutting drum is provided with a cover over the active part of the drum circumference surface mounted on the housing of the drum and in the cover slots are made for the circular knives which are situated on axes in a support mounted also on the housing of the drum. The said loop-closed chain is guided in a horizontal plane with the aid of sprockets so that the dogs mounted on the chain at equal distances are displaced all the time in a plane parallel to the axis of the cutting drum whereas the sprocket before the cutting drum is displaceable.
It is advantageous that the axis of the pushing together drum is askew to the axis of the set of filter segments in the channel. At the outlet of the channel between the pushing together drum the separator a guide shoe is situated which holds up a consecutive segment in the direction of separating while separating the preceding segment out of the stream of the segments by the separator. Nearby the guide shoe a nozzle supplying compressed air is placed, the nozzle being directed towards the area between the guide shoe and the separator so that the stream of the air helps separating of the segment and stabilizes the segment being separated. The said separator constitutes a disc cam, the periphery of the disc cam constitutes a surface which pushes the segment out, whereas on the periphery there may be more than one pushing out surface and the pushing out surfaces, are spaced uniformly on the periphery of the separator.
As an alternative the separator of the segment may have a form of a disc cam, the periphery of which constitutes a surface which pushes the segment out and moreover the cam has an abutting surface which determines axial speed of the segment being separated which is synchronised with speed imparted to the set of filter segments by the worm surface of the pushing together drum. Such a separator may be provided with more than one abutting surface and more than one pushing out surface, whereas the abutting surface and the pushing out surface are spaced uniformly and the abutting surface of the separator is parallel to the front face of the segment being separated.
It is advantageous that the width of the pushing out surface in the last phase of separating is bigger than the length of the segment. The said transferring element in the periphery area constitutes a unit of two discs spaced at a distance and provided with drivers, whereas between the discs a height adjustable support is situated. The drivers may be mounted on the transferring element in a shifting manner, whereas the drivers may be spaced uniformly or non-uniformly on the periphery of the transferring element. Moreover in the area of pushing out the segment being separated a movable supporting element is situated, speed of which is synchronised with rotational speed of the transferring element, the supporting element being situated so that in the area of pushing the segments out a chamber is formed which is used for instantaneous storing the segment until it is collected by the driver, the chamber being formed at the bottom by the top surface of the adjustable support, at one side by the movable supporting element, at the other side by the pushing out surface of the cam and at the top by the cover of the transferring element.
It is advantageous that the movable supporting element constitutes a disc rotary assembled on the axis perpendicular to the transferring element. As an alternative the movable supporting element constitutes an endless belt with the supporting surface parallel to the transferring element. The individual modules are set according to an endwise manner in any sequence. Due to such construction the apparatus is reliable at high speed of compiling groups of segments on the exit path. The application of the guiding element, which presses gently the set of segments especially the first segment after exiting a flute of the cutting drum, ensures controlled guiding of the set of segments in the channel with the axis of the set being parallel to the axis of the flute while drawing out of the flute, and moreover eliminates the first segment inertial springing back after hitting the last segment in the flute by a dog. Placing the chain in a horizontal plane enables easy adjustment of the trajectory of the chain according to the required width of the cutting drum, whereas the dog always hits the centre of the last segment of the set and the position of the dog over the face of the last segment is maintained while the dog leading the segments along the entire length of the guiding channel. The cover over the active part of the cutting drum ensures stabilization of transported filter rods and also transported segments after cutting rods into the sets of segments.
Applying the drum that pushes the segments together, provided with a worm surface of a variable pitch, enables eliminating a gap between sets of segments which appears after removing a dog in the end part of the channel before separating individual segments, whereas the construction of the separator enables full control of the position of the segments being separated, enables avoiding making the axis of the segment askew and ensures high capacity of the apparatus. The arrangement of the transferring element provided with drivers, the separator, the supporting element, the support and the cover enables creating the chamber, in which a segment separated from a set of segments awaits for collecting by a driver, whereas time of awaiting depends on equal or unequal spacing of drivers on the periphery of the transferring element and defines suitable setting of the segment on the exit path in order to compile a required group of segments.